The present invention relates to a setting apparatus for fasteners of the type in which during setting a blind rivet, lock bolt or the like a mandrel thereof is broken. More specifically, the present invention relates to a setting apparatus for blind rivets which includes a mechanism for discharging the broken mandrel from a nose of the setting apparatus through the inside thereof and is suitable for inserting and setting a blind rivet into a workpiece from the position above the workpiece.
A fastener such as a blind rivet or a lock bolt has been well known which comprises a hollow rivet body and a mandrel inserted into this rivet body. Generally, a hydraulic actuated setting apparatus is used in a setting operation for setting the fastener in a workpiece. The setting apparatus is provided with a jaw at a nose defined by the front end of the apparatus to hold the mandrel of the blind rivet. When the mandrel of the blind rivet is inserted into the nose to hold the mandrel with the jaw, while a rivet body of the blind rivet will be projecting from the nose into a mounting hole of the workpiece. When the setting apparatus is triggered, a piston of a pneumatic cylinder is actuated and then this piston is slidably moved in a hydraulic cylinder to produce a high hydraulic pressure. Then, by this hydraulic pressure, the jaw is driven within the setting apparatus in a pull-in direction for pulling the mandrel strongly enough to break or fracture the mandrel at a desired breakable position and to expand a shank of the rivet body so that the rivet body is set in the workpiece by the expanded shank and a flange of the rivet body. The broken mandrel is released from the jaw, and then transferred in the setting apparatus from the front end to the rear end thereof,whereafter the broken mandrel is discharging from the rear end of the setting apparatus or collected by a broken mandrel collecting vessel provided at the rear end of the setting apparatus.
One type of well known conventional blind rivet setting apparatus is disclosed in U.S. Pat. No. 3,898,833. In this type of setting apparatus, a handle with a trigger extends to intersect with an apparatus body extending rearward from a nose of the setting apparatus. This may provide a convenient configuration for being gripped by an operator and may serve various uses. However, this setting apparatus is not suited to the operation for inserting and setting a blind rivet into and in a workpiece from the position above the workpiece in the position higher than the waist position of an operator. This is because when the front end of the setting apparatus is placed on the workpiece located in a position higher than the waist position of the operator from the position above the workpiece, the operator is forced to grip the handle in an unnatural manner, resulting in unpractical operation performance. A setting apparatus suitable for inserting and setting a blind rivet into and in a workpiece from the position above the workpiece.
One example of such a prior art apparatus is shown in FIGS. 1 and 2. In FIG. 1, the setting apparatus I comprises a nose 2, an apparatus body 3 extending rearward (upward in the figure) from the nose 2, and a pneumatic cylinder 5 extending further rearward from the apparatus body 3. A hydraulic cylinder is provided inside of the apparatus body 3 at a position adjacent to the pneumatic cylinder 5. The setting apparatus 1 is formed to extend longitudinally from the nose 2 to the pneumatic cylinder 5 in totality. The apparatus body 3 of the setting apparatus 1 is provided with a handle 6 having a trigger lever 7 attached thereto. An operator may carry out a setting operation of a fastener (not shown) such as a blind rivet from the position above a workpiece by gripping the apparatus body 3 having the handle 6 and directing the nose 2 of the setting apparatus 1 downward. A hanging member 9 is attached to the apparatus body 3 of the setting apparatus 1. As shown in FIG. 2, the hanging member 9 is supported by a power-assist arm 13 to which a cross piece 11 of a supporting post 10 is mounted. Thus, the power-assist arm 13 bears a weight corresponding to that of the setting apparatus 1 to allow load applied to hands of the operator to be reduced and thereby to facilitate the setting operation. A compressed air supply pipe 14 is coupled to the setting apparatus 1. By gripping the trigger lever 7 of the handle 6, compressed air may be introduced into the pneumatic cylinder 5, the operation of which will compress oil in an adjacent hydraulic cylinder to carry out the setting operation, as described and shown hereinafter.
In the vertical type setting apparatus 1 extending longitudinally as shown in FIGS. 1 and 2, a pneumatic cylinder 5 is provided above the rear end (i.e. upper end) of the apparatus body 3, and has no handle intersecting with the apparatus body. Thus, the apparatus may be reduced in size and weight, and is suited to the operation for inserting and setting a blind rivet into and in a workpiece from the position above the workpiece, which position may be higher than the waist position of an operator. However, since the pneumatic cylinder having a large diameter is provided at the rear end or the upper end of the apparatus, the mandrel broken by the pull-action of the jaw is required to get around the pneumatic cylinder 5 in order to be discharged at the rear end of the setting apparatus 1. This is possible by providing a curved broken mandrel discharge path. The broken mandrel discharge path is defined by the reference number 15 in FIGS. 1 and 2. FIG. 3 shows a state in which this broken mandrel discharge path 15 is curved in an area where the path comes out of the apparatus body 3. In FIG. 3, the broken mandrel discharge path 15 is curved in the area 16. If a precedent broken mandrel is jammed in this curved area 16a and a subsequently broken mandrel is provided, the path can be undesirably clogged by the conjuncture between the broken mandrels 18A and 18B shown by dotted lines in FIG. 3.
Another type of prior art blind rivet setting apparatus, different from the setting apparatus 1 shown in FIGS. 1 to 3, is shown in FIG. 4, where there is another setting apparatus 1A in which a nose 2 and apparatus body 3, and a pneumatic cylinder 17 are provided in the longitudinal direction of the setting apparatus with offsetting their axes respectively. In this setting apparatus 18, when a compressed air is supplied to an upper end of a piston 19 of a pneumatic cylinder 17 to move a piston rod 21 into an oil sump 22, the resulting compressed oil is supplied to a hydraulic cylinder 23 provided inside of the apparatus body 3. Then, a hydraulic piston 25 is moved upward to pull up a jaw 26 disposed in the front end of the nose 2. This pull-up force is strong enough to break the mandrel of the fastener held by the jaw 26. In this setting apparatus 18, the broken mandrel can be discharged from an exit 27 through a hollow tube formed at the center of the nose 2 which receives therein a hollow tube of the hydraulic piston 25 shiftably mounted in the apparatus body 3, and thus this discharge path is straight and not curved. This is because the axis of the pneumatic cylinder 17 is offset from the nose 2 and apparatus body 3 and thereby the path is not required to go around the pneumatic cylinder 17. However, this pneumatic cylinder 17 having the axis offset from the nose 2 and the apparatus body 3 leads to a large setting apparatus and heavier setting apparatus as a whole. Thus, this setting apparatus may not be well suited to the operation of inserting and setting a blind rivet into and in a workpiece from the position above the workpiece or in the position higher than the waist position of an operator.
Thus, in a setting apparatus for blind rivets of the type in which setting is achieved by breaking a mandrel of a blind rivet, it is an object of the present invention to provide a compact and lightweight setting apparatus capable of discharging the resulting broken mandrel without any jamming.
In order to achieve the above object, the present invention provides a setting apparatus for blind rivets, constructed such that a mandrel of a fastener is inserted into a hole of a nose at the front end of the setting apparatus, and while a rivet body of the fastener is projected from the nose into a mounting hole of a workpiece, the mandrel is pulled rearward of the nose with a force capable of breaking the mandrel to expand a shank of the rivet body so that the fastener is set onto the workpiece by the expanded shank and a flange of the rivet body, followed by discharging the broken mandrel out of the setting apparatus, wherein the force for pulling the mandrel is obtained from hydraulic pressure of a hydraulic cylinder, the hydraulic pressure being produced by a piston which moves in a pneumatic cylinder adjacent to the hydraulic cylinder. The setting apparatus has the nose thereof aligned with the apparatus body which includes the hydraulic cylinder and the pneumatic cylinder aligned in the longitudinal direction from the front end to the rear end thereof, and a discharge path for the broken mandrel is formed by a hollow tube extending from the mandrel insertion hole at the nose through the apparatus body and the hydraulic cylinder to the rear end of the setting apparatus.
In the aforementioned setting apparatus, the construction in which the nose is arranged with the apparatus body including the hydraulic cylinder and the pneumatic cylinder along the longitudinal direction of the setting apparatus allows the setting apparatus to be reduced in size and weight. Further, since the broken mandrel discharge path extends from the nose through the apparatus body and the pneumatic cylinder to the rear end of the setting apparatus, the discharge path need not be curved. Thus, the broken mandrel may smoothly pass through the discharge path and may be discharged from the setting apparatus without any jamming in the path. Furthermore, arranging the exit of the discharge path at the rear end of the setting apparatus allows an air hose for supplying a compressed air and a hose for discharging the mandrel to be concentrated at the rear end or upper end of the setting apparatus. This provides easy arrangement of such hoses.
In the aforementioned setting apparatus, the broken mandrel discharge tube preferably extends linearly in the longitudinal direction of the setting apparatus. A mandrel collecting device may be attached to a mandrel discharge port of the broken mandrel discharge tube at the rear end of the setting apparatus.
As described above, according to the present invention, arranging the nose, the apparatus body including the hydraulic cylinder and the pneumatic cylinder along the longitudinal direction of the setting apparatus allows the setting apparatus to be reduced in size and weight. Further, since the broken mandrel discharge path extends from the nose through the apparatus body and the pneumatic cylinder to the rear end of the setting apparatus, the discharge path is not curved. Thus, the broken mandrel may smoothly pass through the discharge path and may be discharged from the setting apparatus without any jamming in the path. Furthermore, arranging the exit of the discharge path at the rear end of the setting apparatus allows the air hose for supplying the compressed air and the hose for discharging the mandrel to be concentrated at the rear end or upper end of the setting apparatus. This provides easy arrangement of such hoses. The broken mandrel collecting device may be coupled to the broken mandrel discharge port at the rear end of the setting apparatus. This allows the necessity for coupling the broken mandrel discharge hose to be eliminated, and thereby provide easy arrangement of such hoses, and enhanced operation performance. In addition, the necessity for piping such hoses is eliminated.